public class test2 {
	public static int max(int a ,int b) {
		return a>b?a:b;
	}
	public static int fib(int n) {
		int res=1;
		for (int i = 1; i <=n ; i++) {
			res*=i;
		}
		return res;
	}
	public static int fin(int n ) {
		int a=1;
		int b=1;
		int c=0;
		while(n-2!=0) {
			c=a+b;
			a=b;
			b=c;
			n--;
		}
		return b;
	}
	public  static int max1(int a,int b) {
		return a>b?a:b;
	}
	public static int max1(int a,int b,int c) {
		return a>max1(b,c)?a:max1(b,c);
	}
	public  static double max1(double a,double b) {
		return a>b?a:b;
	}
	public static double max1(double a,double b,double c) {
		return a>max1(b,c)?a:max1(b,c);
	}
	public static int func(int n) {
		int cnt=0;
		if(n==1) {

			return 0;
		}
		if(n==2) {

			return 1;
		} else {
			return func(n-1)+func(n-2);
		}
	}
	public static void main(String[] args) {
		//System.out.println(max(10, max(20, 30)));
//		int n =5;
//		int sum=0;
//		for (int i = 1; i <=n ; i++) {
//			sum+=fib(i);
//		}
//		System.out.println(sum);
		//System.out.println(fin(41));
		//System.out.println(max1(10, 20, 30));
		//System.out.println(max1(1.5, 2.4, 3.6));
		System.out.println(func(41));
	}
}
